Dynamic image transmission system

Abstract

A dynamic image transmission system comprises an input part for inputting image data of an input image, a memory for storing the image data successively input from the input part and for storing transmitting image data which is to be transmitted, an extracting part for extracting a dynamic region which is a portion of the input image and contains a movement by comparing image data of the successive frames stored in the memory, a transmission part for transmitting the image data stored in the memory to a transmission path as the transmitting image data, and a control part for controlling operations of the extracting part and the transmission part during an image transmission mode. The image data related to a first frame of the input image is transmitted as the transmitting image data but only the image data within the extracted dynamic region is transmitted as the transmitting image data with respect to second and subsequent frames.

What is claimed is 
     
       1. A dynamic image transmission system comprising: input means for inputting image data of an input image;   memory means for storing the image data successively input from said input means and for storing transmitting image data which is to be transmitted;   extracting means for extracting a dynamic region which is a portion of the input image and contains a change in image data from that of a previous frame by comparing image data of two successive frames stored in said memory means;   transmission means for transmitting the image data stored in said memory means to a transmission path as the transmitting image data; and   control means for controlling operations of said extracting means and said transmission means during an image transmission mode so that image data related to a first frame of the input image is transmitted as the transmitting image data but only the image data within the extracted dynamic region is transmitted as the transmitting image data with respect to second and subsequent frames;   said transmitting means including means for subjecting only the image data within the extracted dynamic region using both a predetermined interlace and a predetermined data compression before transmission to the transmission path.   
     
     
       2. The dynamic image transmission system as claimed in claim 1 wherein said transmission means includes compression means for subjecting the transmitting image data to a predetermined data compression before transmission to the transmission path. 
     
     
       3. The dynamic image transmission system as claimed in claim 1 wherein said input means includes a camera for picking up the input image and for outputting the image data thereof. 
     
     
       4. The dynamic image transmission system as claimed in claim 1 wherein said transmission means includes a modem for modulating the transmitting image data. 
     
     
       5. The dynamic image transmission system as claimed in claim 1 which further comprises display means for displaying an image of the transmitting image data. 
     
     
       6. The dynamic image transmission system as claimed in claim 1 which further comprises a keyboard coupled to said control means for instructing the image transmission mode. 
     
     
       7. The dynamic image transmission system as claimed in claim 1 wherein said predetermined data compression is selected from a group including a difference pulse code modulation, an adaptive difference pulse code modulation and an adaptive discrete cosine transform. 
     
     
       8. The dynamic image transmission system is claimed in claim 1 wherein said predetermined data compression is selected from a group including one-dimensional data compression and two-dimensional data compression. 
     
     
       9. The dynamic image transmission system as claimed in claim 1 wherein the transmission path is a telephone line. 
     
     
       10. The dynamic image transmission system as claimed in claim 16 wherein said transmission means includes a network control unit which is connected to the telephone line. 
     
     
       11. The dynamic image transmission system as claimed in claim 1 which further comprises reception means for receiving transmitting image data which is transmitted from a said transmitting means of another dynamic image transmission system and received via the transmission path, said control means controlling operations of said reception means during an image reception mode so that the received transmitting image data is stored in said memory means with respect to the first frame and only the picture element data within the dynamic region is rewritten in said memory means with respect to the second and subsequent frames. 
     
     
       12. The dynamic image transmission system as claimed in claim 11 wherein said reception means includes expansion means for subjecting the received transmitting image data to a predetermined data expansion before storage in said memory means. 
     
     
       13. The dynamic image transmission system as claimed in claim 11 wherein said reception means includes a modem for demodulating the received transmitting image data. 
     
     
       14. The dynamic image transmission system as claimed in claim 11 which further comprises display means for displaying an image of the received transmitting image data. 
     
     
       15. A dynamic image transmission system comprising: input means for inputting image data of an input image;   memory means for storing the image data successively input from said input means and for storing transmitting image data which is to be transmitted;   extracting means for extracting a dynamic region which is a portion of the input image and contains a change in image data from that of a previous frame by comparing image data of two successive frames stored in said memory means;   transmission means for transmitting the image data stored in said memory means to a transmission path as the transmitting image data; and   control means for controlling operations of said extracting means and said transmission means during an image transmission mode so that image data related to a first frame of the input image is transmitted as the transmitting image data but only the image data within the extracted dynamic region is transmitted as the transmitting image data with respect to second and subsequent frames;   said extracting means including comparing means for successively comparing corresponding picture element data making up the image data of the two successive frames stored in said memory means, accumulating means for accumulating in said memory means, accumulating means for accumulating a difference between two corresponding picture element data for all of the picture element data, and defining means for defining the dynamic region in which an absolute value of the difference is greater than a threshold value.   
     
     
       16. The dynamic image transmission system as claimed in claim 15 wherein said accumulating means accumulates the difference in a form of a row histogram taken along a direction of rows of picture elements constituting the input image and a column histogram taken along a direction of columns of picture elements constituting the input image. 
     
     
       17. The dynamic image transmission system as claimed in claim ,2 wherein said defining means defines the dynamic region by addresses of top left and bottom right picture elements within the dynamic region. 
     
     
       18. The dynamic image transmission system as claimed in claim ,2 wherein said defining means defines the dynamic region by an address of a top left picture element within the dynamic region, a main scanning width taken along a main scanning direction and a sub scanning width within the dynamic region taken along a sub scanning direction. 
     
     
       19. A dynamic image transmission system comprising: input means for inputting image data of an input image;   memory means for storing the image data successively input from said input means and for storing transmitting image data which is to be transmitted;   extracting means for extracting a dynamic region which is a portion of the input image and contains a change in image data from that of a previous frame by comparing image data of two successive frames stored in said memory means;   transmission means for transmitting the image data stored in said memory means to a transmission path as the transmitting image data;   control means for controlling operations of said extracting means and said transmission means during an image transmission mode so that image data related to a first frame of the input image is transmitted as the transmitting image data but only the image data within the extracted dynamic region is transmitted as the transmitting image data with respect to second and subsequent frames; and   data processing means including first means for comparing picture element data of two mutually adjacent lines with respect to all lines in the first frame, second means for accumulating a difference between the picture element data of the two mutually adjacent lines, third means for generating a line identification code indicative of a position of each line within the frame, and fourth means for generating a no-change code when an absolute value of the difference is less than a predetermined threshold level.   
     
     
       20. The dynamic image transmission system as claimed in claim 7 wherein said transmission means includes compression means for subjecting the transmitting image data to a predetermined data compression before transmission, said transmission means transmitting only the no-change code together with the line identification code when said no-change code is generated by said fourth means.